\documentclass{standalone}


    % GRAPHICS
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{width=7cm,compat=1.3}

\definecolor{blue}{RGB}{0,105,168}
\definecolor{lightblue}{RGB}{0,180,255}
\definecolor{red}{RGB}{217,88,160}
\pgfplotsset{grid style={dashed}}
\begin{document}

\begin{tikzpicture}

\begin{axis}[
	tick label style={/pgf/number format/fixed},
	scaled ticks=false,
  grid=major,
  %ymin=-30, ymax=10.0,
	xtick={-0.949,-0.316,0.316,0.949},
	ytick={-0.949,-0.316,0.316,0.949},	
	xticklabels={-$\frac{3}{\sqrt{10}}$,-$\frac{1}{\sqrt{10}}$,$\frac{1}{\sqrt{10}}$,$\frac{3}{\sqrt{10}}$},
	yticklabels={-$\frac{3}{\sqrt{10}}$,-$\frac{1}{\sqrt{10}}$,$\frac{1}{\sqrt{10}}$,$\frac{3}{\sqrt{10}}$},
	%xmin=-7.5e6,xmax=7.5e6,
  xlabel={In-phase},
  ylabel={Quadrature},
]

    \addplot[color=blue,line width=1pt,mark=x,only marks]
	table [col sep=space]
	{data/iq.txt};

    \addplot[color=red,line width=1pt,mark=o,only marks]
	table [col sep=space]
	{data/iq_comp.txt};



\end{axis}


\end{tikzpicture}
\end{document}